Whats wrong with my computer? (look at pics)

Hi, my computers slowed down over the past few days, and my mouse sticks in places quite oftern and i am getting these errors, i havnt done anything or installed anything recently, but a friend using my computer may have so im not sure whats wrong.

 

Looks like operating system messing up. Not sure though.

 

Same has happend to me.
Just recover XP once more (but recover it without loosing your data on computer) or if you have some updates that you are did not installed do it. Maybe you should install SpyBot - SD Resident, because it can be some of troyans or malvare whatever.

 

Try defragmenting your hard disk? Well defragmenting increases the hard disk speed and fixes general errors,so i'll try that first. if i were you

 

I would like to suggest:
- Uninstall Norton AV, i saw you use it and not update it.
- Install Anti Virus and run it (i prefer Kapersky v8)
- If no virus found, uninstall your program / software which use yhxxxx.dll (shown on your 1st screen capture, i think this come from yahoo)
- See the result, if still have a problem, you could posting here again.

 

Take a look at this thread. There a number of fixes that may work.

 

Try using the XP disk to repair any corrupted files.