Gaming Computer acting up after replacing components

[NunoSnica]

Hey guys, I'm having some trouble with my desktop, and would like to request your help in trying to figure out what's the problem.

I'll start by explaining the situation.

I have this 7/8 year old desktop, which is my main machine and all of a sudden, the mainboard died. I went to a repair shop to get it fixed since I didn't find it in me to make the repair myself.

They repaired it, by replacing the mainboard and the old ram I had because this new board didn't support the old ddr2 sticks.

After I got it back tho, I started having these really weird slowdowns when I do certain stuff.

For example, usually I could watch a livestream, keep chatting on skype, keep a game on facebook open, surf around the web and download stuff at the same time. Anything more than that and I'd obviously start having some delays.
Now, after the repairs, just by watching a livestream and havign a game open on facebook, I start having these strange slowdowns. They die out after closing either the facebook tab or the livestream one.


Also, sometimes, while playing League of Legends, I have the same kind of slowdown for about 20/30 seconds, and then they stop. That usually happens twice per match.

I think this is all the details I can give about my problem(excluding system specs which I'll provide below)


Now about the system specs, I don't really know what mainboard I had before because this desktop was a "gift" of sorts from my older brother (He used it for about 5 years and then gave it to me, I've been using it ever since).

Old specs:

OS: Windows 7 Ultimate 32bit

MB: Unknown

Ram: Two 2gb sticks(4gb total) aData brand(probably not known, I got them cheap from a store in my country)

Graphics Card: Sapphire Radeon HD 2600 PRO

PSU: 500W Stability POWER. I'd really like to provide more info on this, but this piece was replaced about a year ago, and since I didn't have a big budget to get a nice piece, I bought this 25€ generic looking one

CPU: Intel Pentium D CPU 3.20ghz



New specs:

OS: Windows 7 Ultimate 64bit

MB: MSI G41M-P28

Ram: 4gb Corsair CMV4GX3M1A1333C9

Graphics Card: Sapphire Radeon HD 2600 PRO

PSU: Same one from before

CPU: Intel Pentium D CPU 3.20ghz


Sorry for the terrible wall of text, but I'd really like to see if I could fix this problem. The guy at the shop says he doesn't see any problem with the machine, but it clearly isn't completely fixed.

Also, forgive any and all errors, I'm not a native english speaker.


Thanks in advance.


Quick Edit: I don't think I forgot anything about the problem/specs, but if I did, and I remember I'll post them below this edit.


Remembered to add that after I first got this problem, I have formatted the computer several times in hopes of fixing it. Needless to say that I installed all the correct drivers.

 

[Tom Bombadildo]

Hmm...sounds like faulty RAM to me. Could also be dirty contacts as well. Check the contacts first, if they look clean then run Memtest and see if your RAM is good.

 

[NunoSnica]

Thanks so much for a very fast reply, I actually thought about it being a RAM problem, but I didn't really know how I could test it since I don't have another stick. I'll be right back, checking the RAM.


EDIT: I quickly checked the RAM, but I didn't notice anything wrong with it. I'll try out that Memtest right now.

Second edit: I tried Memtest, but the RAM passed the test.

 

[NunoSnica]

I know bumping topics is against the rules, but I'm just bumping to update info.

I tried Memtest, but the RAM passed the test.

 

[Originality]

As a matter of testing (or general upgrading), I would get a new HDD. Install Windows to that, leave the other drives unplugged, and see if that fixes your problem.

Also the CPU is kinda old, so it may be ageing or may have had a bit of dirt or something when being transferred between motherboards.

Last thing I can think of: when you put on the heatsink for the CPU, did you clean the thermal paste and put some fresh paste on? If not, it may be a heat issue (CPU throttling speed to reduce core temps).

 

[NunoSnica]

As a matter of testing (or general upgrading), I would get a new HDD. Install Windows to that, leave the other drives unplugged, and see if that fixes your problem.

I'm going to try and see if I can do that today.

Last thing I can think of: when you put on the heatsink for the CPU, did you clean the thermal paste and put some fresh paste on? If not, it may be a heat issue (CPU throttling speed to reduce core temps).

I doubt this is it, at least about the thermal paste, at the store I told them several times not to forget about it because I've had some problems at another store on my old computer(even older than this one lol xD an old pentium 3)

I have opened my case a few times and checked if all the cables were plugged correctly and stuff but everything was fine.

Another thing I did was try out the on board GPU, but didn't get much better results, so I'm guessing my graphics card isn't the problem. I'm really in a bind about this, so I'm going down to the shop today and see what they'll tell.

But please do keep suggestions coming my way, I really apreciate it.