I used to ask myself that question every time Windows 95 crashed while I was trying to juggle spreadsheets, databases, and e-mail. Hours of crucial work were wiped out in an instant because Windows 95 could no longer keep track of the tangled bits.

If you aren't asking yourself the same question now, you probably will be soon. That's because NT, once the ugly stepchild of Microsoft operating systems, has blossomed into a valuable tool for business-oriented computing. Armed with the same interface as Windows 9x, rock-solid reliability, and effective security features, NT 4.0 has found a home on over 15 million computers.

What's more, Microsoft has made it clear that Windows 98 is its last 16-bit/32-bit hybrid OS. Since all Wintel roads lead to NT, you may have to master this operating system if you want to stay productive.

Not sure whether the upgrade is right for you? See the table below. NT is certainly not for everyone. It's pricey, for one thing. A single-user version of NT Workstation costs about $460 retail (versus about $300 for a full version of Windows 98). Despite NT's improved compatibility, your legacy hardware may not run, since the operating system lacks Plug and Play support. If you run 16-bit apps, your software may not run under NT's strict resource-protection scheme. Finally, NT may simply be too much OS for your old 486 or Pentium classic.

If you do decide to take the leap, put a premium on planning and preparation. The upgrade itself may take 45 minutes, but you should spend hours, if not days, taking stock of your hardware and software. Find NT-compatible drivers for your various devices and save them to disk, and round up your scattered application disks so they're on hand when you need to install them over NT. And don't forget to back up your data!

If you're moving from Windows 95, get a complete inventory of your system. This will help you identify IRQ conflicts and solve other problems that might crop up after you lose the Plug and Play safety net.

1. Select StartûSettingsûControl Panel, double-click the System icon, and click the Device Manager tab.

2. Make sure the Computer item at the top of the list is selected, and click the Print button at the bottom of the System Properties dialogue box.

3. In the Print dialogue box, click the All devices and system summary button and then click OK. This will print an exhaustive report on your system's hardware.

For reports on specific parts of your system, click the Properties button in the System Properties dialogue box. Then select one of the four radio buttons at the top of the Computer Properties dialogue box to review settings for interrupt requests, input/output devices, direct memory access, and memory.

If you're upgrading from Windows 98, click StartûProgramsûAccessoriesûSystem Tools and select System Information. Click the plus sign next to Hardware Resources to see individual assignments of IRQs, DMAs, I/O addresses and other resources.