Ok, I used my 411 in a KT133 comp for weeks without any prob.
A bit of reinstallation (both hardware and software) and I got probs.
I identified 2 problems and I can confirm the solution are different so there are really 2 (at least ) which are:
1/ Continuous Buffer under run and red/orange flashing.
2/ Error when trying to write actual data (not CdSpeed test or whatever) with ‘Hardware Error’ with EVERY software I tried including VSO, Nero,DvdDecrypter & co.
I will do 2 more posts below, one for each problem. Please for these posts to comment. Thanks.