Product Number : GG045AA
Description : HP PAVILION A6142N HOME PC
5188-2622 250-watt (max) power supply (Zinfandel), Bestec ATX-250-12V) - 100-120VAC and 200-240VAC input (switch selectable), 50/60Hz
Your power supply has a minimal 250 watt max. capacity, and it's brand, BESTEC, is well known to be a LOT more likely to malfunction than most brands, and a LOT more likely to damage something else when it fails completely, often it fries the mboard.
Even if you manage to find a video card that can be used with a system that has only a 250 watt power supply, I recommend that you replace the power supply with one made by a brand other that BESTEC ! They have commonly been used on emachines desktop systems for many years, and them failing is probably the number one reason emachines desktop systems fail to boot, and when they fail completely, the number one reason a motherboard in an emachines desktop system is found to be fried after the power supply has been replaced.
Some cheap models of brand name systems other than emachines were/are actually made by the same company that actually makes emachines systems - Trigem, in Korea - and merely have whatever brand names logo, branding stuff, and the brand name's bios version on the computer. When the power supply is found to be the BESTEC brand, that's quite likely.
Your power supply must have at least the minimum capacity required to support a system with the graphics card you are using installed, or the max graphics card you might install in the future.
(Onboard video - video built into the mboard - IS NOT A CARD ! )
If that info is not in the ad for the video card, you can go to the video card maker's web site and look up the specs for the model - often under system requirements - the minimum PS wattage, and, more important, the minimum amperage the PS must supply at 12v is stated. If you don't find that, any card with the same video chipset including any letters after the model number has very similar minimum PS requirements. Some power supplies have two or more +12v ratings - in that case, add those ratings to determine the total +12v current capacity.
If you're a gamer...
In most if not all cases, the max capacity rating of the PS is an intermittent rating. It's recommended that you do not load your PS to any more that 80% of that rating if you are going to be using something that puts a constant load on it, such as playing a recent game for hours on end. In that case, you multiply the min capacity stated for the system with the particular video chipset on the card by 1.25 to find the min. capacity of the PS you should get.
If you need to get a PS with more capacity, you can usually replace it with any decent standard sized standard ATX PS.
Standard (PS/2) power supply size - 86mm high, 150mm wide, 140mm deep, or 3 3/8" h x 5 7/8" w x 5 1/2" d , or very close to that, though the depth can be more or less for some PSs.
Don't buy an el-cheapo PS.
See response 3 in this: