Pc will not start - only power LED blinks

[Dorota]

Hello,
since a few days my PC can no longer turn on. Once I stepped on the Power button starts the power-on LED flashing. One also hears the fans turn up short. If you have 3-4 times the power supply back and off he goes back to normal high. What could be the reason?

I would be looking for a tip.

Data:

• AMD Athlon 3500 +
• MSI K8N Neo4 Platinum
• 512mb RAM
• Nvidia 6600gt

[need Tos]

Which NT is installed?
Have you changed something on the computer, since the problem?

[Dorota]

The power supply is 400W Noname. I have changed nothing on the PC.