No offense on this, but you really should do a search via google or your fav search engine on this yourself. I did a search on 'i845e specifications' and came up with this on the first page:

Processors supported- Intel Pentium 4 (Willamette/Northwood) with 400/533 MHz bus;
- Intel Celeron (Willamette) with 400MHz, Socket 478i845E chipset- Intel® 82645E Memory Controller Hub (MCH)
- Intel® 82801DB Enhanced I/O Controller Hub (ICH4)System memory- Three 184-pin slots for DDR SDRAM DIMM;
- Up to 2GB memory;
- PC1600/2100 memory supportedGraphics- AGP slot supporting 4x modeExpandability- Six 32-bit PCI Bus Master slots;
- One CNR slot;
- Six USB 2.0 ports (2 integrated +4 additional);
- Three IEEE1394 ports (Fireware)Overclockability- FSB frequency range: 100 to 355(!) MHz in 1 MHz steps;
- Changeable voltage of processor, memory, AGP;
- EasyTune v4.0 utilityIntegrated capabilities- Integrated Creative CT5880 (sound);
- Intel 82562ET network controller;
- VIA VT6306 controller for IEEE-1394 busDisc subsystem- 2 UltraDMA/100/66/33 Bus Master IDE channels (supporting up to 4 ATAPI devices);
- Additional IDE Raid controller (Promise PDC20276 chip, 2 IDE channels supporting ATA33/66/100/133 & RAID 0, 1, up to 4 ATAPI devices);
- LS-120 / ZIP / ATAPI CD-ROM supportedBIOS- 2х4MBit Flash ROM
- Award BIOS v.6.00PG with support of Enhanced ACPI, DMI, Green, PnP Features and Trend Chip Away Virus
- DualBIOS technology (two BIOS chips)Miscellaneous- One port for FDD, two serial and one parallel ports, ports for PS/2 mouse & keyboard
- Power indicator onboard
- STR (Suspend to RAM)
- SPDIF Out
- Smart Card Reader support: PS/SC compatible Smart Cards Reader
- Secure Digital Reader and Memory Stick Reader supportedMonitoring- System health status;
- Monitoring of processor's temperature, voltage, speeds of three fansPower control- ACPI/APM
- Wake on modem, mouse, keyboard, LAN, timer and USBPower- Standard 20-pin ATX connector (ATX-PW)
- Additional 4-pin power connectorDimensions- ATX form-factor, 245 x 305 mm(9.63" x 12")

Next time, search around a bit. :cheesy:

he did search, and his search brought him here

Theoretically, that motherboard should accept a pentium 4 533FSB processor of around 3GHZ, if one can be found. Most Pentium 4 processor of that speed are now using an 800MHz FSB, and those would not suit the board.

But you need to be careful, and you really should check on the HP website to see the upgrade potential for that particular PC. 'Name Brand' PCs are usually not as forgiving with upgrades as 'White Box' PCs, and the BIOS of the system may not allow for the necessary clock multiplier settings that would be needed to use the maximum potential of the chipset. Companies like HP actively encourage you to REPLACE your PC, not upgrade it

In short, I can't be sure without checking the HP website, and I'll leave that up to you to do. Post back here if you have trouble.

TKS, I am sorry it was such an inconvenience for you to help me out. I mean this is a tech help board right? I have done a lot of searching for this information, and like you, I found the wrong info. Finally I came here because I know there are great 'helpers' like Catweazle, who assist, not criticize.

Hey Cat, just wanted to let you know that I talked with HP tech support, yes in india, and he said my mobo could support up to a 2.4Ghz pentium 4 without HyperThreading. I am not 100% positive about this. But I found a 2.8Ghz processor that operates at 533 bus speed. Anyways, I think I'll probably just get a new PC in about a year, by then this won't be worth upgrading. Thanks again.

I've just checked HP's website, and there are definitely no BIOS updates available, so if that processor was the limit in BIOS, then I think it'd be correct. Damned if I reckon it's worth upgrading an HP Pavilion, anyway. Damned if I even like working on the things!