This happens after you have changed something of your PC components, so delete your gta_sa.set and you'll be alright, after you delete it just open gta sa single player to get your new gta_sa.set file
The new gta_sa.set file will recognize your graphics card and that will fix the problem
Get another ENB .. there are so many different ENBs, I guess you just used some bugged/ not compatible with SAMP
Here's a good one, but note that it's for high-end PCs http://205.196.120.55/46c9l3u7sytg/8o4k ... Nestwo.rar
BTW Orka's ENB is compatible with SAMP, you can use it