XP Pro freezing after being left alone for awhile

I have a rather new T60p Thinkpad laptop (about 3 months old) and this just started happening. When I leave my laptop, I log off using the "switch user" option so that you have to enter a password to log on, but all my programs are still running. Recently, every time I come back to my computer and open the lid or move the mouse to log back on, the screen freezes. It usually just shows my desktop background, the blue windows xp log on screen will not show up. I have a fingerprint scanner and it will let me scan my finger but it won't log me on. The only thing I can do is hold down the power button and shut off my computer and turn it back on. My computer is relatively clean with no viruses or spyware so I don't know what can be causing this. Can someone give me some info as to what may be causing this or something I can do to fix this? Thanks

 

can u do a restore from the date that this started happening?

cheers ...

 

I don't take backups because it takes up too much hard drive space so I don't think I'd be able to restore.

The only thing I can think of that has changed is that I installed Bit Defender anti virus a couple weeks ago, could this possibly be the cause of the freezing?

 

does not hurt to remove this bit defender and see. u can always re.install it afterward - do it in safemode

cheers ...

 

if u have ur restore option set, u can take a look at it under accesories, system and see if u can set it back to the date before u intalled this extra utility

cheers ...