Windows 7 Now Runs Very Slowly After Hard Shutdown?

I was forced to shut down my computer due to it having frozen up, whilst playing the Battlefield 3 single player. The computer crashed, and after about 5 minutes of rapidly pressing ctrl+alt+delete, and alt+tab, I decided the best way forwards was to force shut it down, by holding the shut down button. After restarting my computer, I noticed it took slightly longer to boot up. Hmm, nothing special. Then, I entered my login credentials, and after a 2-3 minute wait at the 'Welcome' screen, I was presented with a black screen, nothing more. After about 5 minutes, my cursor popped up. Oh, at least I have that. I pressed ctrl+alt+delete again, however after waiting 5 minutes for the screen to pop up, task manager simply would not open. I came back around 30 mins later, and the taskbar and my wallpaper had popped up. However, I pressed the start button to see if it would come up with the menu. Nothing. Cursor stops moving, bam. Another crash. Another forced restart.

This repeats once again, so I decide to head on into safe mode and try to go back to a restore point. Even safe mode is somewhat laggy, however it is not un-usable. After system restore is complete, nothing has changed. I still have to wait around 30 mins for the taskbar to pop up. I then tried using the repair tool you get to try if the computer doesn't start up properly. Doesn't work. My third option is to try out chkdsk, and that is happening as we speak. It has currently been going on for about 14 hrs, and found many corrupt files aparently in stage 4, however many of these files don't appear to be major. Its currently at 16% done, 205675 out of 371465 files processed.System specs wise, I have an Intel i5 460m processor @ 2.3ghz, 4GB RAM, 64bit operating system, and an ATI Mobility Radeon 5650, which I have overclocked to 650mhz core clock speeds, 950 memory clocks, from 450 - 790.