When does the screen begin the 'barcode' display?
1- Immediately (as soon as you turn it on, before POST)
2- During boot
3- After log in/complete Windows load
If 1 - GPU or PC to Screen Cable has failed - start shopping for a new computer. (do not buy another POS Acer) Has the computer been dropped? Have you opened it? Can you open it to check that both ends screen cable are fully seated in their connectors?
2 or 3 - possible driver corruption or incorrect driver installed (highly unlikely, but possible)
Can you boot into Safe Mode? Have you tried the previously mentioned LiveCD?
How can i reinstall the drivers from my graphics processor when i dont have a cd.
Go to acer.com, or whatever, lookup your model and download the latest video drivers.