Here is my version 1.0 of MechEdit. I've been writing it and adding bits to it on and off for years as time allows. I've written it to work under Windows 98, but it seems to work under XP and 95.
I wrote MechEdit to print blank sheets for BattleTech. It developed to print not only blank BattleMech sheets but to print sheets of various BattleMech types, and I've included many of the BattleMechs for 3025 with this program. From there it was a short jump to make the program keep track of damage to BattleMechs and basic information on their pilots so it can be used for players to keep track of their units.
I got the inspiration for this program from a piece of software called MechSheet written by RiTz@step.polymtl.ca. It gave a beautiful output but could only print one size and so it often looked bad when scaled to work on a different printer. It was also pretty basic and didn't allow for a record of damage to be kept.
I have expanded MechEdit to edit and keep track of other BattleTech vehicles (Aerospace fighters, Aircraft, VTOLs, Naval vessels and ground vehicles). I have entered records for all vehicles in the origional 3025 and 3026 source books (except drop ships and the sparrowhawk) as best I can as many of these don't follow FASA's rules on vehicle creation.
I hope you find this program useful. If you have any suggestions or spot any bugs, please do not hesitate to contact me at william.fraser@virgin.net.
I would like to take this opportunity to thank my good friend Adrian Dunn who has been a great help Beta Testing this program and helping me with the BattleTech rules.
Here's a screen shot of what an individual sub-screen looks like:
If you want to see what the printed sheet looks like, here's what a sample sheet looks like: 
Here is the executable, a readme file, help file, files of units to load, and some background images zipped up. Click here to download (651K).