You have to keep this in mind when dealing with older Pentium equipment, both with Laptops and Desktops
The BIOS can be programmed to lock out the faster bus speeds and multipliers that the faster CPU's need in order to run at their rated speeds. Of course there's no way to know if an updated BIOS will resolve this or not until you actually update it and see
Another thing manufacturers did was to use jumper blocks, Galahad seems to know about these however, there should be two sets of jumpers. One determines the bud speed, 33 MHz, 66 Mhz, 100 Mhz, 133MHz, etc.... and the other will determine the multiplier, x2, x2.5, x3, x3.5, etc...
Make sure that the bus speed is set for 66MHz as this is the most common for the older Pentium CPU's, this would make the multiplier be x2.5 for a 166MHz CPU
No then Intel was the first to use mulitplier locks on their faster CPU's, I think starting with the P2, but could have had this done on the P200/233 as well.
Not much too it really, the problem is that most laptops don't have jumper blocks, they may have pads instead, ala, the Amiga
also note that an Overdrive was only rated to work on a desktop machine, not a laptop. The overdrive provided for it's own voltage regulator, multiplier and bus speed, this is why there is a small circuit board under the CPU socket
Good luck with the overclocking