I would try the Talat Sao shopping mall or the LT computer shop (parallel road to Dong Palan)
#4 _oli_ has been a member since 20/5/2011. Posts: 5
Thanks for the suggestions. It turned out I just needed the graphics driver reinstalled and some virus/malware removed.
I got it done at a place called Starcom on Samsenthai Rd just past Wat Si Meuang.