Can burn DVD's but cannot burn CDR's

Please help.

I recently brought a HP M7570 UK PC from PC world :o . After purchase I installed Nero 6, DVD Shrink and another programme. The problem that I have is that I cannot burn CDR’s. The CD’s that I am making cannot be read by my PC or my CD player even though the software that I am using gives me a message that the burn was successful. The CDR’s that I amj using are EMTEC’s which work fine on my old PC. I was told (by a freind) to remove the Sonic software that was already on the PC but this has not helped.

I’ve tried contacting the PC world Tech support but this proved very frustrating (it took a 40 min tel conv. before anyone would even talk about my problem) so I gave up!

The writer that came with the PC is a Lite-on DVDRW SHM-165H6S HP10.

Thanks in advance.