Writing speed problem with Asus CRW-5224A

[Fila]

Hey guys, ok it's like this.

Before last week the writer was burning fine. Around 4min when using 24x.
Now, i turn of my PC (of course), i unplug the writer, i go to my moms place, i install it there, save files from the HDD that i needed to save before the format, format my moms PC, come back home, i plug in the writer again (i never started the PC while the writer was gone) and now when i try to write with 24x it takes 11min and with 48x it takes 8min.

What can it be wrong? I am using Nero 6.3, i uninstalled the program and installed it again and that's not the problem.
Btw, the writer worked fine when saving my moms files.