If it unlocks (or even if it does not) after several minutes, you could check settings -> control panel -> system -> device manager for any yellow ! or ? to see what card may be causing the problem/conflict. Reseating the cards may give a better connection, PC could have been bumped enough to cause a poor connection to an improperly seated card.
If you're asking for technical help, please be sure to include all your system info, including operating system, model number, and any other specifics related to the problem. Also please exercise your best judgment when posting in the forums--revealing personal information such as your e-mail address, telephone number, and address is not recommended.
Win 98 locks at PCI Device Listing