Would this cause a V64 not work?

I made a thread about a my V64 not showing any video, I managed to open the V64 and found this hard stuff around the solder joints, although it looks like rust I'm not sure if this is normal or not (call me stupid, I have no idea about this stuff).
If it's bad, how would I go about cleaning this up?

 

Looks like oxidisation, but it may just be old flux build up.
Give them all a good reheat with a soldering iron (300 degrees will be fine - anymore is overkill), a clean with a hard bristled brush and acetone and then over again with alcohol.

 

is just flux, a reflow may help, may not

 

I'd say it's unlikely to be the cause, but you can reflow it if you want. Avoid dry joints, of course.

Was it working before, or have you never had it working properly? And are you talking about the initial boot up, or playing a ROM?

 

Well it was working fine for nearly a year and just 2 weeks ago it wasn't showing video. I'm just so confused with it right now and no body has been able to help me with it, I understand they're weird systems...

Everything worked beforehand, playing ROMs, booting everything, just now no video and I should add that the system was off and unplugged for 2 weeks so it's really weird.

 

Hexigon, I recon I can definitely help you with that.

 

That's great, when you can throw me a PM.