Just wanted to state that you can pick up a 40GB or larger IDE HDD cheap these days. I bought a 120GB Refurb IDE HDD off of Newegg like 3 months ago for my daughters Pentium 4 system to upgrade away from the 40GB and its a good drive and only cost $9.99 with free shipping and has either a 90 day or 1 year warranty. I ran crystal disk on it and it shows that the drive was not power cycled many times, but had 18,000 hours of runtime. I have seen drives run well beyond 30k hours of runtime and keep chugging with no problems, so it was a good deal.
You might run into the 137GB limitation.
http://www.seagate.com/support/kb/disc/tp/137gb.pdfbut....
Intel offers drivers to support the full capacity of drives larger than 137 GB on motherboards
equipped with the Intel 810, 810E, 810E2, 815, 815, 815E, 815EP, 815P, 820, 820E, 830M,
830MP, 830MG, 840, 845, 850, or 860 chipset.
I have an old motherboard with the Intel 845 GLVE running a Pentium 4 2.00Ghz single-core and I tested it with XP, Vista, and Windows 7 32-bit Home Premium on 1GB of DDR 266Mhz FSB RAM.XP Pro SP3 = ( Clean install ) Runs perfect speed on it, however ran faster on SP2 clean install and slowed some after all updates and SP3. Ok multitasking.
Vista 32-bit = was laggy but ran, poor multitasking. (*Note upgraded to vista from XP so it may have inherrited the xp driver for GPU)
Windows 7 32-bit Home Premium = (Clean install ) was laggy, and I ran into driver issues with the Integrated Video of the 845GL chipset, and had to force Windows 7 to use Windows XP drivers since driver support for the 845 chipset ended at XP. * With Vista you may have to also force it to take a XP driver for integrated video if you dont have a video card added. Single-Tasking Only and CPU running 100% for long periods of time. ** Looked for an old GeForce 4 MX 440 PCI video card with 64MB RAM that I had to try in it vs integrated video, but video card was M.I.A to test with.
***Note: Speed and Multitasking related to Pentium 4 socket 478 2.00Ghz with 1GB of DDR 266Mhz RAM. If I had a better CPU or more RAM it probably would have ran better. My motherboard is TriGem Imperial GL_VE 20021111 with Intel 845GL chipset, out of an old eMachine tower that originally had a 2Ghz Celeron and 128MB RAM when I took it out of a pile of computer junk going out for recycle back in 2007.
What are you running for a CPU, RAM, and GPU?
Also ...
There are IDE to SATA adapters available...
While these do work most of the time, a SATA drive converted to work on IDE I wouldnt suggest, as for for around the same price as one of these converters you can get a PCI SATA I - 1.5 or SATA II - 3.0 adapter and have better performance. I upgraded a Pentium 4 2.8Ghz from ATA 100 to SATA 1.5 and it helped speed up performance with boot and loading large files etc. The SATA HDD controller was a PCI which was 2 port 1.5mb/s and was a StarTech which I picked up for like $15 back in 2008. ** Just had to go into BIOS and tell it to boot off of this SATA controllers attached 300GB SATA drive vs the 160GB IDE HDD. I then left the 160GB in the system and formatted it to use it for redundant backup space of important data as part of a scheduled backup between the 300GB SATA and the 160GB IDE nightly.