Thanks for the reply Ray and the links which were very informative but I still have the basic question of what will or won't work in my PC. I mostly use it for web browsing (dial-up) and word processing. No gaming or other resource hogging activities. So performance needs are minimal. Hard drives on the before-mentioned sites are listed as IDE Ultra ATA 100, IDE Ultra ATA 133, Ultra320 SCSI (60 and 80 pin)and SATA. I know I can't use the SATA but am in a quandry as to which of the others would be compatible. Also, if I do use a HD that doesn't use the ultra DMA standard, will I have to make an adjustment in the Bios to accomadate it? Thanks for any suggestions as I'm afraid my present drive is about to jump ship!!! -Phil Williams- In a message dated 1/19/2008 12:35:16 PM Pacific Standard Time, [log in to unmask] writes: I looked up Ultra DMA and discovered that it is a form of IDA/ATA which is faster and uses an 80 wire 40 pin cable. Check out the following two articles I found on Google. http://www.pcguide.com/ref/hdd/if/ide/modesUDMA-c.html http://www.pcguide.com/ref/hdd/if/ide/confCable80-c.html You might want to stick with a UDMA drive to keep your performance up to what the old drive was. Later, Ray Parrish [log in to unmask] wrote: > I am looking to replace an aging Hard Drive in my Compaq Presario 5425ks > desktop. The HP/Compaq site lists my HD as an 80GB (5400 rpm) Ultra DMA. > Browsing HDs at Newegg and TigerDirect, the term "UltraDMA" isn't used so I'm unsure > of what drives might be compatible. I'm leaning toward either WD or Seagate > 80GB 7200 rpm at an "affordable" price. > Are there other terms or associated numbers I should look for while shopping? > > Thanks, > -Phil Williams- **************Start the year off right. Easy ways to stay in shape. http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489 The NOSPIN Group has added a new feature on our website, web based bulletinboard for questions and answers: Visit our sister website at http://nospin.com