PC not responding. Need help..

[Kalyan]

Hi, my pc has slowed down and giving me errors now and then. My Sony DVD RW does not read dual layer disks and cds properly. I have a 400W stock PSU. and my configuration is in the sig. Is the power supply the culprit? Do I need to upgrade the PSU or can I run the setup with it? Recently reading some of the drives on the hard disk is taking too long, both in XP and Vista.
At times, it is taking ages on the loading screen.

Thanks in advance

[Psychosocial]

It can be a problem with your HDD and DVD-RW rather than PSU...

[Kalyan]

The HDD is new one. but ya.. the dvdrw came from the service center. and it is malfunctioning. Can I be sure that the stock PSU is able to power my pc?

[dixit8611]

u can check ur psu by a multimeter. But i think it can be virus or corrupted window files ....... may be u ned to reinstall ur os but it can be better if u take a screenshort of errors and post it here........