problem in pcr - (Jul/15/2011 )

I did my pcr and it had very dood bands but suddenly now It dosent have bands. I dont know what thing changed? Please help . Very thanks.

primers degraded? template degraded? uncalibrated thermalcycler?

Are you using good quality filter tips when loading your samples? I found a lot of contamination issues were simply from the plastics I was using. Try the A+ Barrier Tips from Alkali Scientific... they are relativiely inexpensive and they work great.