Sure. I would format it first if you're mixing it with an old drive, or do a clone of your old drive. I use maxblast 5.0, a free download, to prep drives. If your old drive is sata, I would plug in the ssd after booting into windows. Then go to the device manager and click on the small icon that checks for new devices, located on the right side at the top of this window. Then use the software to prep or clone the new drive.
Installing a SSD in the 435MT is not straightforward. There are a few "Catch 22" issues in that regard. TRIM support is absolutely vital with a SSD. Without it the SSD will eventually become as slow or slower than a regular HDD. In order for TRIM to function, the SSD must use an AHCI driver. It also will enable NCQ, giving you all the speed your SSD is capable of over SATA 2.0, which is a max of 3 Gbits/second. A side benefit is that it makes your SATA and eSATA ports hot-plug capable, though not necessarily hot-swap capable. (The difference is hot-plug means you can add a drive but not remove it, while hot-swap means you can add or remove a drive with the system running.)
Unfortunately, the Intel X58 + ICH10 chipset on the XPS 435MT's mobo is not full featured. Dell limits the chipset's capabilities. While the onboard Intel SATA controllers can support AHCI, they run in IDE mode by default. The BIOS is also limited to say the least, more like crippled actually. In the BIOS, under Advanced Chipset Features > SATA Mode, there is only a choice between IDE or RAID with IDE being the default. However, by selecting RAID for the SATA Mode, AHCI is enabled on all four SATA ports as well as eSATA. Of course, if you enable RAID after your OS is installed, everything on your SSD or HDD will be lost and you will have to reinstall the OS again. So, enable RAID in the 435MT's BIOS before installing the OS on your new SSD.
The next problem you will likely encounter is a failed install of your OS. This is described in the MS Knowledge Base Article 2466753 available here:
This is a known issue with both Windows 7 and Windows 8. Don't know about Vista though. There are workarounds involving editing the system registry by creating keys, subkeys, and values, as well as workarounds to the workarounds depending on what controller your SSD uses. Assuming at some point you get your system up and running from your SSD, there is one other problem that crops up when you insert a blank optical disk into your burner. Your system will likely either freeze or crash entirely. This is due to your optical drive(s) also running AHCI drivers when they should be using IDE/UDMA. When you select the RAID option for the SATA Mode in the BIOS, all the SATA ports switch over to AHCI. So, before you use your optical drive(s), check in Device Manager to see if you can change the driver for the optical drive's SATA controller in the OS to IDE/UDMA.