For a while now I've had a corrupt, unusable version of Ubuntu on a different partition. I had both Windows 7 and corrupt Ubuntu 12.04 LTS. It was completely destroyed, and I felt it was a bit of a waste just keeping it there, so I completely deleted the partition and restored it to my original hard disk. I then decided to simply reinstall Ubuntu for dual-boot again, going for the 13.04 beta version. I had to split my partition again, and Ubuntu works like a charm, alongside Windows. I had been using Ubuntu too much in the past bunch of days to notice what issues this has caused. When I returned to Windows today, I experienced the most major slowdown of my life. It is practically dead. After the blue Welcome screen, the screen goes absolutely black. Nada. Nothing. I can't Ctrl+Alt+Del, I can't open up Command Prompt. Nothing. I decided maybe it was just being incredibly slow and recorded that it took 15 entire minutes to show the desktop and its icons. The icons are meant to be highlighted when passed over by my cursor; however this time there was a 10 second delay. Double-clicking anything on my desktop to open would just cause explorer.exe to stop working, and I'd be greeted by that black screen again for another 15 minutes. I thought it was a simple disk fragmenting issue. I was going to open up disk defragmenter, but of course, given the state of my laptop, it was near impossible. A few hours later I finally manage to open it up, and it turns out that all of my disks aren't fragmented as they are defragmented every week. Now of course there are lots of issues that could cause a slowdown, but remember that this happened only immediately after Ubuntu was installed. Can anyone help? Thanks in advance!