If you have multiple partitions, a backup may be a more complex. It depends upon the ties between the Registry & the other partitions, as to whether they must be backed up concurrently.
Also, if you've changed the hardware since the backup, you may need to change it back before a restore. (So always create a new backup immediately after modding the hardware!!)
These are offered in no particular order - just as they came to me (with some comments either added/amended or removed as seems appropriate),
With the expiry of support of Win9x, many of these programs, if updated, may cease to support ME and/or 9x
http://www.acronis.com/products/trueimage/ - TrueImage
http://www.arjsoftware.com - ARJ Archiver
http://www.betterbackup.com.au/ - Retrospect CD Backup
http://www.bootitng.com/ BootItNG, has a variety of backup capabilities: Copy to HDD, or Image to HDD or to CD/DVD. It is also an effective Boot Manager and partition manager (I bought two licenses I liked it so much!)
Because it has its own OS, BING doesn't care about your OS - but it can only do full partition or disk images, not partial or differential backups
To install & use beyond 30 days, $34.95....and a Technician License is only $69.95!
http://www.han-soft.com/habt.php - Auto Backup
Simple Backup (appears now to be owned by Sonic - and therefore not free, but the v4.7 is still available here for free, and works in WinME, if you can figure out how! - I think you need to have CD-burning software pre-installed, but haven't tried it)
http://www.karenware.com/ - PtReplicator (Free)
http://www.lifesaverbackup.com/
http://www.pcmag.com/ Lots & lots of downloads.
http://www.ranish.com/part/ Ranish Partition Manager
http://www.simtel.net/pub/dl/58307.shtml Backups
http://www.thirdstar.net/thirdstar_datarecovery.htm Data recovery
http://www.insideoe.com/ Outlook Express Backups, etc.
http://www.v-com.com/product/Partition_Commander_Home.html Partition Commander (new link!)
http://www.veritas.com Backup apps
http://www.xxcopy.com/ Yabumoto's Detailed Procedure Copy (Free)
http://www.zeleps.com/ Partition re-sizer (Free)