I've had some issues lately with the game so I just unistalled and am trying to reinstall, but now the GTA window pops up to install but says my system is incompatible, but it clearly is not as I've been playing the game on this particular PC with no changes to the PC.

 

Any ideas? Thanks guys.

Can you give us more details please? Are you running the GTA IV installation as administrator? Legal copy of the game? 

I've had some issues lately with the game so I just unistalled and am trying to reinstall, but now the GTA window pops up to install but says my system is incompatible, but it clearly is not as I've been playing the game on this particular PC with no changes to the PC.

 

Any ideas? Thanks guys.

What are your specs?

Yeah, spec's we are gonna need.

Well, since the OP said he has been able to play the game before, I don't think the specs is the issue here, more likely he forgot to set the "run as administrator" flag on GTAIV.exe and LaunchGTAIV.exe

Have you tried right clicking the LaunchGTAIV.exe file and running it with compatibility mode? Which operating system are you currently running?

I've resolved the install issue. However, I now have an issue with mods not working. In particular, scripts.

 

I've freshly installed LCPDFR, along with some other scripts and none of them work, including the trainer. These are the same exact files I've been using, some for more than a year. I've not got it on 'read only', and I've tried installing the mods separately and none work. The game runs and loads fine in story mode.

 

I've got all the required scripthook and such which is provided with most of them in the downloads.

Still, are you running the game as administrator? 

Yes, the game is set to always run as admin.