You may already have consulted this MS trouble-shooting information.
http://www.microsoft.com/technet/prodtechn…m.mspx?mfr=true
Since you are able to navigate around and perform applications (virus scan) in SAFE Mode.
And Since you have access via Recovery Console….
That may rule-out problems with hardware, or at least localize it to instances when Normal Windows attempts to load.
I'd tend to wonder if you have some corrupted operating system files in Windows.
Unfortunately, you can only run System File Checker (sfc /scannow) when in Normal Mode.
Therefore, if you rule out the other "causes" listed by MS, you may benefit from a Repair Installation from Recovery Console.
Since you have a "serious" problem, you may want to back up important documents and files before performing any more tests.
Repair Installation is "supposed" to be "non-destructive", but still a good idea to back up documents and files.
If you have another machine, you could install this Hard Drive (configured as Slave) into a known-good machine. That would allow you to save documents and files before performing repairs.
Or if you are comfortable using a bootable pre-windows environment, like Bart's PE or the UltimateBootDisk, you could fire up your machine via bootable CD to perform your documents and files backup, and also do additional diagnosing and repair in the same way.
Sounds like the "problem" just started occuring "out of the blue" without any physical changes (new hardware) or configuration changes (new application software) ? If so, it's probably not a bad IDE connection or poorly seated PCI card or RAM Stick. Instead, if it's Hardware, then some piece of Hardware has gone faulty on you. Failing RAM, Failing IDE ribbon, Failing CPU. But the "most likely" cause would be "heat". Second most likely is failing Power Supply.
So crack open that case and inspect for dirt/dust bunnies, especially clogged air-intake at the bottom-front of your machine, and accumulation of dirt/dust on the HeatSink cooling fins of your CPU and Video Card. Blow out the dirt/dust with compressed air. While you have the case open, inspect for bulging capacitors, and poorly seated PCI cards. Also check the IDE ribbons. Make sure all your Fans are running freely and vigorously……… but don't keep your machine powered up with the case open for more than a minute or two because of cooling issues.
Best Regards