Hi,
What is the exact Model of your Compaq Presario?; there are literally hundreds of them.
Next, you posted a problem with your Vista installation in the Windows7 hardware forum. Did you do an upgrade from Vista to Windows7? Or perhaps you couldn't find another sub-forum to post this on.
In any case, if you did not upgrade your Presario to Windows7, and are running Vista 32bit SP1, you do not have the latest Service Pack, that is SP2 for Vista. The first thing I would do is to download and install the SP2 for Vista, and see if the problem persists.
Newer video cards such as 1GB and larger can often cause video problems with older hardware without full OS update support.
SP2 install may very well solve this problem.
There are 2 other possibilities as well. Does your Presario have an on-board Video port (VGA)? If so, REMOVE your EVGA 1GB card from the PC completely and retest with just the built-in video port. If the problem still occurs, you may have a faulty Monitor or TV. Try hooking up a Monitor that's working Ok on another working computer in your home or borrow one from a friend. If the problem persists even on a tested Monitor from another Computer, then it's not your TV/HDMI setup, but rather a fault in your PC. If your Presario doesn't have a built-in video port (VGA), leave the EVGA 1G card in and test with another tested Monitor as before. If the problem persists, then you have a hardware failure elsewhere in your PC and you'll need to troubleshoot further to find it.
If your problem persists, you likely have a hardware problem somewhere else in your PC and you'll need to run Hardware diagnostics to find the faulty component. There are 2 common causes for failures like this in PCs that are over 5 yrs. of age:
1) Faulty hard drive
2) Faulty RAM stick(s)
To test #1, download the free SEATOOLS* drive test program from seagate.com and run BOTH short and long tests. If SEATOOLS returns any errors, your Hard Drive has failed and must be replaced. Attempt to make a Backup of all needed Personal Information such as documents, photos, music, movies, E-mail, etc. to external media before removing the drive from the PC. If you are unable to do this, remove that drive and replace it. Set that failed drive aside for further data recovery.
Reinstall Windows Vista 32bit from your installation Media and retest. If the drive did fail, this should solve your problem.
To test #2, download the free MEMTEST* memory test program via Google. Test each stick of RAM individually for a minimum of 8 passes. If MEMTEST returns any errors you have a failed RAM stick and it must be replaced. Test ALL the RAM sticks you have and then reinsert all of them once they pass the MEMTEST, and run MEMTEST one final time with all (1-4 typicall) sticks installed. If MEMTEST returns any errors after the 8 passes, you'll need to begin replaced pairs of RAM sticks with new ones until MEMTEST completes without errors with all sticks installed.
*Note: Downloading both the SEATOOLS and MEMTEST programs will give you an ISO file image file, which you will then need to burn to CD or DVD blank disc. For this I recommend the free IMGburn program available via Google. Use the IMGburn program to create a bootable disc that contains first the SEATOOLS test and a 2nd disc that contains the MEMTEST program. You should be able to fit both on blank CD disc; but if you only have blank DVD disc this will work just fine. Remember to change the Boot Order or Boot Preference in the boot screen (F9, F10, F11, F12 key, check your owner's manual) so your Presario can find the boot disc you are trying to load (SEATOOLS or MEMTEST).
Retest your PC again. If you indeed found a faulty hard drive or RAM stick(s), this should solve your problem.
If neither test produced any errors, you most likely have a serious problem with your Motherboard if you reach this point, and it should be tested and replaced if faulty. If you don't have the money to replace it, you should consider buying a replacement computer either used or new. Used PCs with Vista WITH TV/HDMI support can be had for under $100 US; and brand new Windows8.1 PCs can be had for under $250 US.
Let us know how it goes or if you have any questions along the way.
Good luck,
<<<BIGBEARJEDI>>>