What is the problem?

The ATX specification only allows voltages to swing +/- 10% from their nominal value. Good PSUs should not swing more than 3% under the worst load conditions and should be within 1-2% when idle.

This means that the absolute maximum voltage value for your 5 volt rail should be 5.5 volts. At 5.6 something has gone horribly wrong internally. You will need to replace your PSU

May I ask what is the make and model?

  i recently bought it , only been 2 months. It came with my Pc Case . It's Cooler Master's 420 W. I won't be able to buy a new one for atleast 3 months. there aren't any errors anymore when i bootup only on the asus program. However, could this be a temporary problem or permanent. I mean it's only .100 more than 5.500v , I've searched online and seen people with having errors at 6v .

You should be able to exchange it if it's only been 2 months. That would be covered under warranty

No   there is only 3 Day checking warranty since it came with the Pc Case. Oh well, i guess i'll be using it till it stops working.

I wouldn't. The overvolting could destroy whatever components are attached to the 5 volt rail. You need to stop using it ASAP and contact Coolermaster for a replacement. All Coolermaster PSUs should carry a 2-5 year warranty

Oh, well i'll contact the store from where i bought it and ask them. Thanx alot for your help.