Hi Faldirianda......
since this is a ''recent'' issue, a
System Restore may solve it.... you could also run
Spybot S&D, to remove any Malware from your machine.
regarding your RAM issue, if your running a 32bit OS you'll be limited to a maximum RAM allocation space of 4gb, this must also include VRAM (RAM attached to your GFX card), & any bios functions....
a 64bit OS has a much higher threshold for RAM allocation.
SK